Lock mechanism for telescoping spar



Oct. 10, 1967 J. R. THOMPSON 3,346,231

7 LOCK MECHANISM FOR TELESCOPING SPAR Filed Jan. 29, 1965 is @4 h 2 "1iJAMES R.THOMPSON I INVENTOR.

AT TORN E 75 United States Patent 3,346,281 LOCK MECHANISM FORTELESCOPING SPA R James R. Thompson, Seattle, Wash., assignor toWashington Iron Works, a corporation of Washington Filed Jan. 29, 1965,Ser. No. 429,003 7 Claims. (Cl. 28758) ABSTRACT OF THE DISCLOSURE Aportable telescoping spar in which dogs hinged to the lower spar sectionsustain the upper spar section, being so formed that the same positivelypreclude retraction from said sustaining position unless the uppersection is raised a prescribed distance above the sustained position.

This invention relates to portable spars for use in logging or otherlike or similar operations, and pertains especially to atelescoping-type portable spar in which an upper section is telescoically associated with a lower section. The purpose is to provide a sparhaving considerable height when in an upright operating condition, whilepermitting the length to be shortened preparatory to lowering the sparinto a horizontal position in course of moving the spar from one toanother operating site, the shortened length allowing the move to bemade with considerably greater ease than would otherwise be the case.

For its principal objects, the invention purposes to provide atelescoping spar in which the joint between the upper and lower sectionsof the extended spar is of advanced design, and particularly to providefor the spar a perfected means for releasably locking the two sectionsagainst endwise displacement when the same are in their operatingextended condition.

A further important object is to engineer into the spar a locking meanswhich is caused to perform its locking function automatically as theupper section reaches a predetermined point in its extension movement.

As a further object still the invention aims to provide a lock so formedand operated that the same produces a loud clang when the lockingfunction is performed so as to give audible notice thereof to theoperator controlling the extension of the spar.

These and other objects and advantages of the invention will appear andbe understood in the course of the following description and claims, theinvention consisting in the novel construction and in the adaptation andcombination of parts hereinafter described and claimed.

In the accompanying drawing:

FIGURE 1 is a fragmentary vertical sectional view illustrating atelescoping spar having joint and lock mechanism embodying the preferredteachings of the present invention, the section line being shown at 11in FIG. 2.

FIG. 2 is a fragmentary horizontal sectional view on line 22 of FIG. 1;and

. FIG. 3 is a fragmentary vertical sectional view on line 3-3 of FIG. 2.

Referring to said drawing, the upper section of the telescoping spar isdenoted by the numeral 10, and the lower section by 11. The uppersection is received within the lower section. Substantial clearance isprovided between the two sections throughout the greater portion of theslide motion, with a piloting fit being established at two verticallyspaced points as the upper section nears its upper extreme limit oftravel. The piloting points have a close tolerance, say .020 diametralclearance, and are provided in each instance between the internalmachined surface of an outer guide ring, as 12 and 13, and the externalmachined surface of an inner ring, as 14 and 15. These outer guide ringsare welded or otherwise made a fixed part of the lower spar section andthe inner guide rings, similarly, are welded or otherwise made a fixedpart of the upper spar section. The two spar sections are desirably offabricated construction and are so illustrated in FIG. 1. To giveperhaps greater clarity, FIG. 3 deletes the division lines between theintegrally joined parts. These parts include, as an integral componentof the upper spar section 10, a bearing ring surrounding the upper sparsection in a position spaced above the latters upper guide ring 14.

The bearing ring has a thrust-taking shoulder 17 at the bottom which isdisposed perpendicular to the axial line of the spar, and presents acurtailed taper at the top. The bevelled flank which this taper providesis denoted by 18, and the upwardly facing flat 0r truncation by 19. The

function of the flat 19 is to engage a stop carried by the lower sparsection and thereby provide an upper extreme limit to which the uppersection may travel when the spar is being extended. This stop iscomprised of an inturned flange 20 formed at the head end of a bonnet 21extending upwardly as a nose prolongation of the lower spar section 11.The bonnet proper is spaced a moderate distance above a thickened headend part 22 of the lower spar section and has depending feet 23 atequidistantly spaced intervals of the circumference bearing upon saidhead end of the lower spar section. Bolts 24 secure the bonnet to thespar section. For ease of assembly the honnet is split on a diameter andhas its two halves secured together by bolts 25 (see FIG. 2).

While not shown in the drawing one of the two spar sections presents akey working in a key-way which is provided by the other spar section.This is conventional with telescoping spars to prevent relative rotationas the two sections are telescoped.

The upper spar section 10 is raised and lowered within the lower sparsection 11 by power. This means therefore is no part of the presentinvention and suflice it to say that the same may be performed in theusual or a suitable manner. The bonnet permits the upper section to beraised to a position whereat the thrust shoulder 17 of its bearing ringis elevated a fair distance above the head end 22 of the lower sparsection.

The locking mechanism of the present invention comprises a set ofbell-cranks 26 each mounted by a hinge pin 17 for reciprocal swingmotion about an axis which is tangent to a circle having the axis of thespar as its center. The hinge pins each have their ends journaled in arespective pair of separated cars 30 which are integral with the lowerspar and project from the external surface thereof. Each of thebell-cranks occupies a plane radial to the spar midway between anadjacent two of said depending feet 23.

The working arms of the bell-cranks extend upwardly from the hinge pinand have an angular configuration when viewed from the side to eachpresent an inturned dogging end 31 which, in the reciprocal swing actionof the bell-crank, moves inwardly and outwardly between an advancedoperating position whereat the dog underlies the thrust shoulder 17 ofthe bearing ring into and from a retracted inoperative position whereatsaid dog clears the bearing ring. When occupying said operatingposition, the dog has the thrust shoulder seated firmly thereon anditself bears firmly upon the head end 22 of the lower spar section.

The power arms 32 of the bell-cranks extend outwardly from the hinge pinand pivotally connect with the upper end of the connecting rod 33 forthe piston of a doubleacting air cylinder 34 having its lower endpivoted, as at 35, to an ear 36 integral with the lower spar section.The several cylinders are connected for gang operation by flexible hoses37 and 38 extending between the cylinders and a control valve (notshown), the valve permitting air under pressure to be supplied from asupply source to either end of the cylinders, or dumped from thecylinders. A spring 40 acts upon a keeper 41 to urge the arm 32 upwardlyso that the dog 31 normally occupies the position in which it is shownin FIG. 1.

The force of the springs 40 is overpowered by air pressure when it isdesired to retract the dogs preliminary to lowering the upper sparsection, and it will be understood, when such lowering is to beperformed, that the upper spar section must first be momentarily raisedin the moderate degree necessary to provide clearance for the dogs toswing outwardly. When raising the upper spar section within the lowerspar section the pressure of the springs is augmented by air pressuresupplied to the lower ends of the cylinders 34. As a consequence, thedogs, which are pressed outwardly by the bevel 18 as the upper sparsection nears the upper extreme limit of its permitted travel, aredriven inwardly with considerable force when the continued rise of thebearing ring brings its thrust, shoulder above the dogs. The loud clangwhich results as metal strikes metal is audible throughout the fullextent of a logging yard, signalling the operator to discontinue theupward travel being given to the upper spar section and lower said uppersection into its operating position whereat the weight of the upper sparsection is passed through the dogs directly from the bearing ring to thehead end of the lower spar section, with the dogs being locked by suchweight load against retraction. This loading is such that shouldpressure air be accidentally fed to the cylinders after the two sparsections have been locked in the manner described the same would beineffective to retract the dogs.

It is believed that the invention will have been clearly understood fromthe foregoing detailed description of my now-preferred illustratedembodiment. Changes in the details of construction may be resorted towithout departing from the spirit of the invention and it is accordinglymy intention that no limitations be implied and that the hereto annexedclaims be given the broadest interpretation to which the employedlanguage fairly admits.

What I claim is:

1. In a telescoping spar of a type which stands upright when in itsoperating position, in combination: a lower spar section providedadjacent its upper end at spaced intervals of the circumference withupwardly facing support means, an upper spar section held againstturning relative to the lower spar section and received for telescopingslide movement within the lower section, said upper section adjacent itslower end being provided with a respective downwardly facing surface foreach of said support means spaced circumferentially of the upper sectionin correspondence with the spacing of the support means and.

serving as thrust shoulders, said shoulders when the spar is extended toits full height beingraised to a level somewhat higher than the leveloccupied by the support means, a respective lever for each of saidsupport means and its related shoulder having an inverted L-shape whenviewed from the side with the upright leg of said L being hinged to thelower spar section for swing motion about an axis tangent to a circlehaving the axis of the spar as its center and the horizontal leg of theL extending as a dog radially inwardly relative to the extended spar andby said swing action moving into and out of a position whereat the uppersurface of the dog underlies the shoulder and the under surface overliesthe support means, and means for moving the dogs in said radialmovement, the upper section of the spar, when the spar is in anoperating condition, occupying a level such that its weight is passeddirectly through the dogs from the thrust shoulders to the supportmeans, a limit stop being provided prescribing a higher level to whichthe upper section can be raised, the dog-forming leg are said radialmovement travelling a path which is interrupted by said shoulder whenthe spar is in its operating condition and thus requires that the upperspar section be first raised a prescribed distance before the dog can beretracted preliminary to a lowering of the upper spar section into thelower spar section.

2. A telescoping spar as claimed in claim 1, means being provided toyieldingly urge the dogs inwardly into operating positions.

3. A telescoping spar as claimed in claim 2 in which the thrustshoulders are produced by the bottom face of a ring surrounding theupper spar section and made an integral part thereof, the upper portionof the ring being bevelled, said bevel pressing the dogs outwardlyagainst the force of said yielding means as the ring traverses the dogsin course of raising the upper spar section.

4. A telescoping spar as claimed in claim 1, each of said leverscomprising one arm of a respective bell-crank having the other armextending outwardly from the hinge axis, the means for moving said dogsradially of the spar comprising for each dog a respective double-actingvertically extending pneumatic jack having one end attached to the lowerspar section and the other end attached to the outwardly extending armof the bell-crank.

5. A telescoping spar as claimed in claim 4, the thrust shoulders beingproduced by the bottom face of a ring surrounding the upper spar sectionand made an integral part thereof, the upper portion of the ring beingbevelled, said bevel pressing the dogs outwardly, against the yieldingforce of pressure air supplied to the pneumatic jack, as the ringtraverses the dogs in course of raising the upper spar section.

6. A telescoping spar as claimed in claim 5, the thrust shoulders beingproduced by the bottom end face of a ring surrounding the upper sparsection and made an integral part thereof, a bonnet being provided whichsur-' mounts the lower spar section in surrounding relation to the upperspar section and is formed at its top end with an inwardly directedflange engaged by the upper end face of the ring to serve as said limitstop for the upward movement of the upper spar section relative to thelower spar section.

7. In a telescoping spar of a type which stands upright when in itsoperating position, in combination: a lower spar section, an upper sparsection received for telescoping slide movement within the lower sparsection and provided adjacent its bottom end with a plurality ofdownwardly facing thrust shoulders which become exposed when the uppersection is raised to a height placing the' spar in an operatingcondition, a plurality of dogs, one for each of said shoulders, hingedto the lower spar section for movement radially of the spar into and outof an operating position where the same underlie the exposed shouldersand pass the weight of the upper spar section into the lower sparsection, a set of double-acting pneumatic jacks each having one endattached to the lower spar section and the other end to a respective oneof the dogs for yieldingly powering the dogs inwardly into and outwardlyout of said operating position, said dogs and the upper spar sectionbeing each composed of a resonant metal and being each so formed andarranged that when the dogs are powered into said operating position thedogs References Cited UNITED STATES PATENTS Goett.

Smith et a1.

Lee 52-115 Badertscher et a1. 52115 10 Bender et a1 52-1 15 Lebourg285-302 Bourassa 52632 Johnson et a1. 52115 Lawrence 285298 CARL W.TOMLIN, Primary Examiner.

W. L. SHEDD, Assistant Examiner.

1. IN A TELESCOPING SPAR OF A TYPE WHICH STANDS UPRIGHT WHEN IN ITSOPERATING POSITION, IN COMBINATION: A LOWER SPAR SECTION PROVIDEDADJACENT ITS UPPER END AT SPACED INTERVALS OF THE CIRCUMFERENCE WITHUPWARDLY FACING SUPPORT MEANS, AN UPPER SPAR SECTION HELD AGAINSTTURNING RELATIVE TO THE LOWER SPAR SECTION AND RECEIVED FOR TELESCOPINGSLIDE MOVEMENT WITHIN THE LOWER SECTION, SAID UPPER SECTION ADJACENT ITSLOWER END BEING PROVIDED WITH A RESPECTIVE DOWNWARDLY FACING SURFACE FOREACH OF SAID SUPPORT MEANS SPACED CIRCUMFERENTIALLY OF THE UPPER SECTIONIN CORRESPONDENCE WITH THE SPACING OF THE SUPPORT MEANS AND SERVING ASTHRUST SHOUDLERS, SAID SHOULDERS WHEN THE SPAR IS EXTENDED TO ITS FULLHEIGHT BEING RASIED TO A LEVEL SOMEWHAT HIGHER THAN THE LEVEL OCCUPIEDBY THE SUPPORT MEANS, A RESPECTIVE LEVER FOR EACH OF SAID SUPPORT MEANSAND ITS RELATED SHOUDLDER HAVING AN INVERTED L-SHPED WHEN VIEWED FROMTHE SIDE WITH THE UPRIGHT LEG OF SAID L BEING HINGED TO THE LOWER SPARSECTION FOR SWING MOTION ABOUT AN AXIS TANGENT TO A CIRCLE HAVING THEAXIS OF THE SPAR AS ITS CENTER AND THE HORIZONTAL LEG OF THE L EXTENDINGAS A DOG RADIALLY INWARDLY RELATIVE TO THE EXTENDED SPAR AND BY SAIDSWING ACTION MOVING INTO AND OUT OF A POSITION WHEREAT THE UPPER SURFACEOF THE DOG UNDERLIES THE SHOULDER AND THE UNDER SURFACE OVERLIES THESUPPORT MEANS, AND MEANS FOR MOVING THE DOGS IN SAID RADIAL MOVEMENT,THE UPPER SECTION OF THE SPAR, WHEN THE SPAR IS IN AN OPERATINGCONDITION, OCCUPYING A LEVEL SUCH THAT ITS WEIGHT IS PASSED DIRECTLYTHROUGH THE DOGS FROM THE THRUST SHOULDERS TO THE SUPPORT MEANS, A LIMTSTOP BEING PROVIDED PRESCRIBING A HIGHER LEVEL TO WHICH THE UPPERSECTION CAN BE RAISED, THE DOG-FORMIGN LEG IN ITS SAID RADIAL MOVEMENTTRAVELLING A PATH WHICH IS INTERRUPTED BY SAID SHOULDER WHEN THE SPAR ISIN ITS OPERATING CONDITION AND THUS REQUIRES THAT THE UPPER SPAR SECTIONTHE FIRST RAISED A PRESCRIBED DISTANCE BEFORE THE DOG CAN BE RETRACTEDPRELIMINARY TO A LOWERING OF THE UPPER SPAR SECTION INTO THE LOWER SPARSECTION.